Breukink E, van Kraaij C, Demel R A, Siezen R J, Kuipers O P, de Kruijff B
Department of Biochemistry of Membranes, Center for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands.
Biochemistry. 1997 Jun 10;36(23):6968-76. doi: 10.1021/bi970008u.
The interaction of nisin Z and a nisin Z mutant carrying a negative charge in the C-terminus ([Glu-32]-nisin Z) with anionic lipids was characterized in model membrane systems, and bacterial membrane systems. We focused on three possible steps in the mode of action of nisin, i.e., binding, insertion, and pore formation of nisin Z. Increasing amounts of anionic lipids in both model and natural membranes were found to strongly enhance the interaction of nisin Z with the membranes at all stages. The results reveal a good correlation between the anionic lipid dependency of the three stages of interaction, of which the increased binding is probably the major determinant for antimicrobial activity. Maximal nisin Z activity could be observed for negatively charged lipid concentrations exceeding 50-60%, both in model membrane systems as well as in bacterial membrane systems. We propose that the amount of negatively charged lipids of the bacterial target membrane is a major determinant for the sensitivity of the organism for nisin. Nisin Z induced leakage of the anionic carboxyfluorescein was more efficient as compared to the leakage of the potassium cation. This lead to the conclusion that an anion-selective pore is formed. In contrast to the results obtained for nisin Z, the binding of [Glu-32]-nisin Z to vesicles remained low even in the presence of high amounts of negatively charged lipids. The insertion and pore-forming ability of [Glu-32]-nisin Z were also decreased. These results demonstrate that the C-terminus of nisin is responsible for the initial interaction of nisin, i.e., binding to the target membrane.
在模型膜系统和细菌膜系统中，研究了乳酸链球菌素Z（Nisin Z）以及在C端携带负电荷的乳酸链球菌素Z突变体（[Glu-32]-Nisin Z）与阴离子脂质的相互作用。我们聚焦于乳酸链球菌素作用模式中的三个可能步骤，即Nisin Z的结合、插入和孔形成。发现在模型膜和天然膜中，增加阴离子脂质的量会在所有阶段强烈增强Nisin Z与膜的相互作用。结果揭示了相互作用三个阶段对阴离子脂质的依赖性之间存在良好的相关性，其中结合增加可能是抗菌活性的主要决定因素。在模型膜系统和细菌膜系统中，当带负电荷的脂质浓度超过50 - 60%时，可观察到Nisin Z的最大活性。我们提出，细菌靶膜中带负电荷脂质的量是生物体对乳酸链球菌素敏感性的主要决定因素。与钾阳离子泄漏相比，Nisin Z诱导的阴离子羧基荧光素泄漏更有效。由此得出结论，形成了阴离子选择性孔。与Nisin Z的结果相反，即使存在大量带负电荷的脂质，[Glu-32]-Nisin Z与囊泡的结合仍然很低。[Glu-32]-Nisin Z的插入和孔形成能力也降低了。这些结果表明，乳酸链球菌素的C端负责乳酸链球菌素的初始相互作用，即与靶膜的结合。
